Liquid coating composition



Patented Sept. 18, 1951 LIQUID COATING COMPOSITION John R. Fisher, Jr.,Dayton,-hio, assignor .to Industrial. Metal Protectives, 1110., Dayton,Ohio, a corporation of Delaware No Drawing. Application November 9,1949, 1

Serial No. 126,452

This invention relates to corrosion resisting coatings. Moreparticularly, it relates to coatings which are continuous and insulatethe base metal against the action of constituents found in theatmosphere and in water. Still more particularly, it relates to animproved protective coating composition and the'process formanufacturing same.

Protective coatings for surfaces, to be effective, must be continuous.The dried coatings must be insoluble in liquid mediums with which theycome in contact and be impervious to corrosive elements. In addition,the coatings must have high tenacity for the base to Withstand abrasionand shock incident'to the normal use.

In my application, Serial No. 790,233, filed December 6, 1947, entitledCoating Composition and Method of Making, there was disclosed animproved protective coating consisting of resin, vegetable drying oil,driers, and zinc dust.

This composition has excellent corrosion resistance, tenacity andflexibility. While these properties are excellent, the surface hardnessand abrasion resistance fell short of that desired for certain purposes.

It is an object of the present invention to overcome the limitations anddisadvantages of the methods heretofore utilized.

It is another object of this invention to provide a coating of improvedsurface hardness.

It is a further object to provide a coating of increased abrasionresistance.

It is another object of the present invention to provide a coating whichcan be prepared in advance of use.

It is still another object of this invention to provide a coating whichmay be rapidly'air dried to tough adherent films.

It isa further object of this invention to produce' an anti-corrosioncoating using finely divided metal powders which, if used as a basecoat, permits superimposing of additional coatings without intermediatetreatments.

It is another object of the present invention to provide a simple methodof preparing a coating composition containing finely divided metalswhich do not rapidly oxidize and gel.

These and other objects and advantages will become apparent from thefollowing description:

The improved coating composition is prepared bymixing at roomtemperature a solution of a low acid resin, a solution of a modifiedsynthetic resin, such as a modified alkyd resin, a solvent capable ofdissolvingv both types. of resin, metallic drier, an, aromaticdistillationv residue,.and. finely divided metallic powder.

9 Claims. (01. zed-20 This composition or suspension can be applied byspraying, by brushing, or by dipping. The coating applied may behardenedby either air drying or force drying methods. If the composition isutilized as an undercoat, it may be overlaid with enamels, wrinklefinishes, or any of the industrial finishes. As an undercoat, thecomposition needs only a short period for surface drying, followingwhich an overcoat can be directly applied, and both coatingssimultaneously baked to dryness.

Heretcfore anti-corrosion coatings or primershave customarily beenthoroughly dried and in addition many of such coatings must haveadditional treatments to render them satisfactory for the application offinished coats to avoid ultimate destruction of the finished coats bythe primercoat or the formation of bubbles, lumps,v etc. under thefinish coat.

The coating of the present invention, when. used as a primer coat, hasdeveloped the un-- expected property of permitting the finish coat beingapplied after a few minutes of air drying of the primer, without anyfurther treatment of the primer.

It is also possible to bake both the primer coat After four hours ofairdrying, the coating of this invention is hard enough to allowpacking" and shipping of the articles. In twelve hours: the coating hasacquired its final hardness which. is essentially higher than coatingsproducedi heretofore. If the production is to be accelerated, it isadvisable to use forced drying. The final coating obtained thereby,however, is not at all superior to those finished by air drying.

Baking or'forced drying may be carried out at temperatures in the rangeof approximately 208 F. to 400 F., the preferred temperature being atabout 225 F. In the latter case a drying time of about one hoursuffices. If drying is carried out with infra-red light, heating foronly 15 minutes may be found necessary.

The low-acid resins operative for the process a to per cent solutions:.1

Vegetable drying oils, such as oiticica oil, tune oil, dehydrated castoroil, linseed oil, raw or blown, perilla oil are all operative in thecompositions of this invention.

Xylol, toluol, naphtha, mineral spirits, and petroleum solvents are thesolvents preferred for the compositions of this invention.

As the drier, a mixture of cobalt and lead naphthenates and/or a mixtureof cobalt and lead linoleates, in the form of a 4 per cent solution,have been found satisfactory. A portion of these driers may also bereplaced by the corresponding manganese salts.

The modified synthetic resins which impart the hardness and abrasionresistance to this composition are preferably modified alkyld resins,such as phenol modified alkyl resin or maleic acid modified alkyl resin.

The commonest form of alkyl resin and the one most extensively used incommerce is the condensation product formed by the reaction of phthalicacid with glycerol and similar polyhydroxy compounds.

The preferred resin is the phenol modified phthalic acid-glycerolreaction product, which product is utilized in this composition inquantities ranging from 10 to 40 per cent by weight of the resin contentof the composition.

A number of aromatic distillation residues have proven satisfactory asinhibitors of the oxidation of the composition. Creosote oil inparticular is preferred. Such equivalent material as naphthols,di-pentene and the like may be used for this purpose. The quantity ofthe inhibitor will vary in accordance with the time delay desiredbetween mixing and use.

In general, quantities ranging from approximately .005 per cent toapproximately 0.25 per cent may be used. A quantity corresponding to 0.1per cent by weight of the composition has been found to increase storagelife by 6 to 12 months.

The finely divided powder used in this coating composition may becomminuted metals, such as zinc, lead, aluminum, magnesium, cadmium, oralloys thereof. For the intended use powders such as zinc have afineness such that 90 per cent averages less than 6 microns in size.

In other words, material is of such fineness that 90 per cent will passthrough a U. S. standard 400 mesh sieve. Preferably, the powder shouldaverage 3 microns or smaller. Finely comminuted powders of this typewill constitute approximately 1-00 to 350 per cent by weight of thesolution in which the powders are mixed.

The following proportions of ingredients were found to give satisfactoryresults:

60 to 70 fi. ozs. low-acid resin solution containing 50 to 60 per centresin 7 to 25 fl. ozs. modified synthetic resin 16 to 24 fl. ozs.solvent fl. oz. cobalt drier n. oz. lead drier 16 to '20 lbs. zinc dust.05 to 2 fi. ozs. creosote oil The compositions are illustrated by thefollowing examples:

Example I 1486 lbs. phthalic acid-glycerol resin solution containing 50to 60 per cent resin 476 lbs. phenol modified phthalic acid-glycerolresin 574 lbs. VM&P naphtha 4 453 lbs. Stoddard solvent 14 lbs. leaddrier (naphthanate or linoleate) 8 lbs. cobalt (naphthanate orlinoleate) 1 pint creosote oil Zinc dust Example II 64 n. ozs. phenolformaldehyde resin solution containing 50 to 60 per cent resin 8 fl.ozs. maleic acid modified alkyd resin 16 11. ozs. VM&P naphtha /2 fi.oz. cobalt linoleate fl. oz. lead naphthanate fl. oz. creosote oil 20lbs. zinc dust All of the above mixtures were applied on articles to becoated and then allowed to air dry; air dried for about 10 minutes; andthen baked as described.

The coatings obtained by the treatment above described are considerablyimproved as to such characteristics as hardness, abrasion resistance andrelated properties.

It will be understood that while there have been given herein certainspecific examples of the practice of this invention, it is not intendedthereby to have this invention limited to or circumscribed by thespecific details of materials, proportions, or conditions hereinspecified, in view of the fact that this invention may be modifiedaccording to individual preference or conditions without necessarilydeparting from the spirit of this disclosure and the scope of theappended claims.

I claim:

1. A liquid coating composition comprising a dispersion of 16 to 20pounds zinc dust, the particle size of which is not larger than 6microns and having an average particle size of 3 microns at least percent of which is capable of passing through a U. S. standard 400 meshscreen dispersed in 60 to 70 fiuid ounces solution containing 50 to 60per cent low acid resin of the class consisting of melamine formaldehyderesins, phenol formaldehyde resins, phthalic acid-glycerol resin, estergum resins and dammar gum resins having an acid number not exceeding '7in said solution, said solution further containing 5 to 25 fiuid ouncesmodified synthetic resin of the class consisting of phenol modifiedalkyd resin and maleic acid modified alkyd resin ranging from 10 to 40per cent by Weight of the resin content of the entire composition, 16 to24 fiuid ounces solvent and about 1 fluid ounce drier.

2. A liquid coating composition comprising a dispersion of 16 to 20pounds zinc dust, the particle size of which is not larger than 6microns and having an average particle size of 3 microns at least 90 percent of which is capable of passing through a U. S. standard 400 meshscreen dispersed in 60 to '70 fluid ounces solution containing 50 to 60per cent low acid resin of the class consisting of melamine formaldehyderesins, phenol formaldehyde resins, phthalic acid-glycerol resin, estergum resins and dammar gum resins having an acid number not exceeding '7in said solution, said solution further containing 5 to 25 fiuid ouncesmodified synthetic resin of the class consisting of phenol modifiedalkyd resin and maleic acid modified alkyd resin ranging from 10 to 40per cent by weight of the resin content of the entire composition, 16 to24 fluid ounces solvent and about fluid ounce cobalt drier and fluidounce lead drier.

3. A liquid coating composition comprising a dispersion of 16 to 20pounds zinc dust, the particle size of which is not larger than 6microns and having an average particle size of 3 microns at least 90 percent of which is capable of passing through a U. S. standard 400 meshscreen dispersed in 60 to 70 fluid ounces solution containing 50 to 60per cent low acid resin of the class consisting of melamine formaldehyderesins, phenol formaldehyde resins, phthalic acid-glycerol resin, estergum resins and dammar gum resins having an acid number not exceeding 7in said solution, said solution further containing to 25 fluid ouncesmodified synthetic resin of the class consisting of phenol modifiedalkyd resin and maleic acid modified alkyd resin ranging from to 40 percent by weight of the resin content of the entire composition, 16 to 24fluid ounces solvent .and about 1 fluid ounce drier and .05 to 2: fluidounces creosote oil.

4. A liquid coating composition comprising zinc dust, the particle sizeof which is not larger than 6 microns and having an average particlesize of 3 microns at least 90 per cent of which is capable of passingthrough a U. S. standard 400 mesh screen, said zinc dust constituting100 to 350 per cent by weight of the solution in which it is mixed,dispersed in a solution comprising about 1486 pounds phthalic acidglycerol resin, about 476 pounds phenol modified phthalic acid-glycerolresin, about 574 pounds naphtha, about 453 pounds stoddard solvent andabout 14 pounds lead drier and about 8 pounds cobalt drier.

5. A liquid coating composition comprising zinc dust, the particle sizeof which is not larger than 6 microns and having an average particlesize of 3 microns at least 90 per cent of which is capable of passingthrough a U. S. standard 400 mesh screen, said zinc dust constituting100 to 350 per cent by weight of the solution in which it is mixed,dispersed in a solution comprising about 1486 pounds phthalic acidglycerol resin, about 476 pounds phenol modified phthalic acid-glycerolresin, about 5'74 pounds naphtha, about 453 pounds stoddard solvent andabout 14 pounds lead drier and about 8 pounds cobalt drier and about 1pint creosote oil.

6. A liquid coating composition comprising about pounds zinc dust, theparticle size of which is not larger than 6 microns and having anaverage particle size of 3 microns at least 90 per cent of which iscapable of passing through a U. S. standard 400 mesh screen dispersed inabout 64 fluid ounces solution containing 50 to 60 per cent phenolformaldehyde resin, 8 fluid ounces maleic acid modified alkyd resin,about 16 fluid ounces naphtha, and about 1 fluid ounce drier.

7. A liquid coating composition comprising about 20 pounds zinc dust,the particle size of which is not larger than 6 microns and having anaverage particle size of 3 microns at least 90 per cent of which iscapable of passing through a U. S. standard 400 mesh screen dispersed inabout 64 fluid ounces solution containing 50 to per cent phenolformaldehyde resin, 8 fluid ounces maleic acid modified alkyd resin, 16fluid ounces naphtha and about fluid ounce cobalt linoleate and about /2fluid ounce lead naphthanate.

8. A liquid coating composition comprising about 20 pounds zinc dust,the particle size of which is not larger than 6 microns and having anaverage particle size of 3 microns at least per cent of which is capableof passing through a U. S. standard 400 mesh screen dispersed in about64 fluid ounces solution containing 50 to 60 per cent phenolformaldehyde resin, 8 fluid ounces maleic acid modified alkyd resin,about 16 fluid ounces naphtha, and about 1 fluid ounce drier and aboutfluid ounce creosote oil.

9. A liquid coating composition comprising about 20 pounds zinc dust,the particle size of which is not larger than 6 microns and having anaverage particle size of 3 microns at least 90 per cent of which iscapable of passing through a U. S. standard 400 mesh screen dispersed inabout 64 fluid ounces solution containing 50 to 60 per cent phenolformaldehyde resin, 8 fluid ounces maleic acid modified alkyd resin,about 16 fluid ounces naphtha, and about fluid ounce cobalt linoleateand about fluid ounce lead naphthanate and about fluid ounce creosoteoil.

JOHN R. FISHER, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,942,757 Ilifi et al. Jan. 9,1934 2,326,623 Crosby Aug. 10, 1943 2,343,925 Pike Mar. 14, 19442,346,624 Straus Apr. 11, 1944 2,353,053 Mitchell July 4, 1944 2,436,420Clayton Feb. 24, 1948 2,493,020 Osdal et'al Jan. 3, 1950 2,509,875McDonald May 30, 1950

1. A LIQUID COATING COMPOSITON COMPRISING A DISPERSION OF 16 TO 20POUNDS ZINC DUST, THE PARTICLE SIZE OF WHICH IS NOT LARGER THAN 6MICRONS AND HAVING AN AVERAGE PARTICLE SIZE OF 3 MICRONS AT LEAST 90 PERCENT OF WHICH IS CAPABLE OF PASSING THROUGH A U. S. STANDARD 400 MESHSCREEN DISPERSED IN 60 TO 70 FLUID OUNCES SOLUTION CONTAINING 50 TO 60PER CENT LOW ACID RESIN OF THE CLASS CONSISTING OF MELAMINE FORMALDEHYDERESINS, PHENOL FORMALDEHYDE RESINS, PHTHALIC ACID-GLYCEROL RESIN, ESTERGUM RESINS AND DAMMAR GUM RESINS HAVING AN ACID NUMBER NOT EXCEEDING 7IN SAID SOLUTION, SAID SOLUTION FURTHER CONTAINING 5 TO 25 FLUID OUNCESMODIFIED SYNTHETIC RESIN OF THE CLASS CONSISTING OF PHENOL MODIFIEDALKYD RESIN AND MALEIC ACID MODIFIED ALKYD RESIN RANGING FROM 10 TO 40PER CENT BY WEIGHT OF THE RESIN CONTENT OF THE ENTIRE COMPOSITION, 16 TO24 FLUID OUNCES SOLVENT AND ABOUT 1 FLUID OUNCE DRIER.